In my humble opinion, the sounds are passable but not great. It's a bit like the default Electrostar soundset, in that they've obviously been recorded from actual stock but parts of it sound...well, "off". In my experience the Class 14 in real life sounds throatier with more rattle and roar - sorry, I'm not too great at describing sounds.
My disclaimer here is that my encounters with Class 14s have purely been on preserved railways.
I'm slightly disappointed in DTG that two of the four provided scenarios are - once again - training scenarios, but there's a few player-made activities in the pipeline at least.
At the end of the day, 8 quid for it isn't too bad at all. Although I have to say, where is the blue one, DTG?